GEOTECHNICAL REPORT Big Bend Hot Springs Project Big Bend, Shasta County, California Prepared For: Big Bend Hot Springs Project, LLC TABLE OF CONTENTS GEOTECHNICAL REPORT BIG BEND HOT SPRINGS PROJECT BIG BEND, SHASTA COUNTY, CALIFORNIA 1.0 GENERAL................................................................................................................................................................. 1 1.1 PROJECT UNDERSTANDING............................................................................................................................ 1 1.2 STUDY PURPOSE ................................................................................................................................................. 1 1.3 PREVIOUS WORK PERFORMED ....................................................................................................................... 1 1.4 SCOPE OF SERVICES........................................................................................................................................... 2 2.0 FINDINGS ................................................................................................................................................................ 2 2.1 FIELD INVESTIGATION..................................................................................................................................... 2 2.2 SITE CONDITIONS.............................................................................................................................................. 3 2.2.1 Surface Conditions................................................................................................................................................... 3 2.2.2 Subsurface Conditions............................................................................................................................................... 3 2.3 GEOLOGIC CONDITIONS ................................................................................................................................. 4 2.3.1 Regional Geology ..................................................................................................................................................... 4 2.3.2 Local Geologic Setting .............................................................................................................................................. 5 2.3.3 Groundwater .......................................................................................................................................................... 5 3.0 GEOLOGICAL HAZARDS...................................................................................................................................... 6 3.1 GEOLOGIC HAZARD ZONES............................................................................................................................ 6 3.2 FAULTING & SEISMICITY .................................................................................................................................. 6 3.2.1 Seismic Setting ........................................................................................................................................................ 6 3.2.2 CBC Design Recommendations .................................................................................................................................. 7 3.3 LANDSLIDES........................................................................................................................................................ 7 3.4 LIQUEFACTION AND LATERAL SPREADING................................................................................................ 7 3.5 EXPANSIVE POTENTIAL ................................................................................................................................... 8 3.6 SOIL CHEMISTRY ................................................................................................................................................ 8 4.0 ENGINEERING PROPERTIES OF SIGNIFICANT EARTH MATERIALS................................................ 10 4.1 TERRACE DEPOSITS (ALLUVIUM).................................................................................................................. 10 4.2 COLLUVIUM....................................................................................................................................................... 10 5.0 CONCLUSIONS AND RECOMMENDATIONS............................................................................................... 11 5.1 GENERAL ........................................................................................................................................................... 11 5.2 FAULTING .......................................................................................................................................................... 11 5.3 LANDSLIDES...................................................................................................................................................... 11 5.4 LIQUEFACTION POTENTIAL.......................................................................................................................... 11 5.5 EXPANSIVE POTENTIAL ................................................................................................................................. 11 5.6 SITE PREPARATION AND GRADING ............................................................................................................ 11 5.6.1 Stripping.............................................................................................................................................................. 11 5.6.2 Existing Utilities, Wells, and/or Foundations ............................................................................................................ 12 5.6.3 Scarification and Compaction................................................................................................................................... 12 5.6.4 Keying and Benching .............................................................................................................................................. 12 5.6.5 Wet/Unstable Soil Conditions................................................................................................................................. 12 5.6.6 Site Drainage ...................................................................................................................................................... 13 5.6.7 Excavation Characteristics & Bulking...................................................................................................................... 13 5.6.8 Temporary & Permanent Slopes............................................................................................................................... 13 5.6.9 Overexcavation & Subdrains................................................................................................................................... 14 5.6.10 On-Site Soil Materials ....................................................................................................................................... 14 5.6.11 Imported Fill Materials - General......................................................................................................................... 14 5.6.12 Materials - Granular......................................................................................................................................... 15 5.6.13 Placement & Compaction ................................................................................................................................... 15 5.7 UTILITY TRENCHS AND TRENCH BACKFILL.............................................................................................. 15 5.7.1 Trenches and Dewatering......................................................................................................................................... 15 5.7.2 Pipe Zone Backfill................................................................................................................................................ 16 5.7.3 Trench Zone Backfill............................................................................................................................................. 16 5.7.4 Controlled Low Strength Backfill............................................................................................................................. 16 CGI: Copyright 2011 i CG11GR033 TABLE OF CONTENTS (continued) GEOTECHNICAL REPORT BIG BEND HOT SPRINGS PROJECT BIG BEND, SHASTA COUNTY, CALIFORNIA 5.7.5 Placement & Compaction ...................................................................................................................................... 16 5.7.6 Trench Subgrade Stabilization ................................................................................................................................. 17 5.7.7 Trench Plugs......................................................................................................................................................... 18 5.8 FOUNDATIONS ................................................................................................................................................. 18 5.8.1 Minimum Footing Embedment and Dimensions .......................................................................................................... 18 5.8.2 Allowable Bearing Capacity....................................................................................................................................